A British scientist whose work has touched on some of the greatest questions in physics, from the nature of the big bang to the size of physical reality, has won the largest monetary prize on the planet.

Set up in 1973 by the late John Templeton, a Wall Street billionaire who described himself as "an enthusiastic Christian", the prize honours a living person who has made "exceptional contributions to affirming life's spiritual dimension". Templeton stipulated that the cash value of the award must always be higher than the Nobel prizes.

"Doing science made me realise that even the simplest things are hard to understand and that makes me suspicious of people who believe they've got anything more than an incomplete and metaphorical understanding of any deep aspect of reality," he told the Guardian. "I participate in occasional religious services which are the customs of the society I grew up in. I'm not allergic to religion."

In 2003, Rees put humanity's odds of surviving the next 100 years at 50-50, citing threats from high-tech catastrophes to environmental impact in his book, Our Final Century.

Speaking ahead of the announcement, Rees criticised the confrontational stance that Dawkins and other "professional atheists" take in debates over science and religion. "I think all of us are concerned about fanaticism and fundamentalism and we need all the allies we can muster against it," he said.

"By peering into the farthest reaches of the galaxies, Martin Rees has opened a window on our very humanity, inviting everyone to wrestle with the most fundamental questions of our nature and existence."